Thymosin Beta-4 Fragment (Ac-LKKTETQ)
A synthetic fragment of Thymosin Beta-4 that promotes cell migration, angiogenesis, and tissue repair. One of the most popular healing peptides, frequently stacked with BPC-157.
TB-500 helps your cells move to where they need to be for healing. It works by affecting actin, a protein that controls cell movement. This promotes new blood vessel growth at injury sites, reduces inflammation, and helps your body rebuild damaged tissue from the inside out.
Primary use case. Extensive Tb4 preclinical data on tissue repair across muscle, tendon, skin, corneal, and cardiac tissue. Cell migration and angiogenesis mechanisms directly support healing.
Anti-inflammatory properties and tissue repair mechanisms support joint recovery. Commonly used alongside BPC-157 for joint injuries.
Promotes tissue repair and has anti-inflammatory effects relevant to aging. Dermal healing research suggests skin quality benefits.
Tb4 promotes dermal healing and has been shown to stimulate hair follicle stem cells in preclinical models.
Thymosin Beta-4 was originally identified as a thymic hormone involved in immune cell maturation. Some immune modulation properties.
Not a primary gut peptide. BPC-157 is preferred for gut applications.
Promotes muscle repair but not a growth promoter.
Limited data on neuroprotection.
Not relevant.
Not relevant.
TB-500 binds to actin monomers, promoting the formation of new blood vessels (angiogenesis) and cell migration to wound sites. The LKKTETQ sequence is the actin-binding domain responsible for sequestering G-actin monomers, which regulates cytoskeletal dynamics necessary for cell motility. TB-500 also promotes extracellular matrix remodeling via metalloproteinase regulation, reduces inflammatory cytokines, and has anti-apoptotic properties. It upregulates integrin-mediated signaling for ECM remodeling and fibroblast activation.
Most common community protocol. Loading phase builds systemic levels. Can inject anywhere subcutaneously (not site-specific like BPC-157).
After loading phase, reduce frequency. Many users maintain for 4-8 additional weeks.
The most popular healing peptide stack. Complementary mechanisms. BPC-157 injected near injury site, TB-500 injected anywhere.
TB-500 promotes angiogenesis and cell migration. These are the same mechanisms tumors exploit for growth and metastasis. Theoretical risk of promoting tumor growth or spread.
No safety data. Cell migration and angiogenesis effects could affect fetal development.
No safety data in pediatric populations.
Anti-inflammatory effects via cytokine modulation
Promotes angiogenesis through VEGF pathway activation
Modulates extracellular matrix remodeling
The gold standard healing stack. BPC-157 works via VEGF/NO, TB-500 via actin/cell migration. Complementary mechanisms provide broader healing coverage. Most popular peptide combination in the community.
GHK-Cu adds collagen synthesis. Triple stack with BPC-157 for comprehensive healing.
No known interactions. GH secretagogues may complement healing indirectly.
No known interactions.
Hannappel E - Ann N Y Acad Sci (2007) - Review
Comprehensive review of Tb4 development from thymic hormone to actin-sequestering peptide to cytokine supporting wound healing. Documents biological effects including cell migration, angiogenesis, and anti-inflammatory properties.
Limitations: Review article, covers full-length Tb4, not TB-500 fragment specifically.
Sosne G - Expert Opin Biol Ther (2018) - Review
Tb4 has important applications in ocular repair. Phase 3 clinical trials using Tb4 to treat dry eye and neurotrophic keratopathy were ongoing at time of publication.
Limitations: Covers full-length Tb4 for ophthalmic use, not TB-500 fragment for systemic healing.
Philp D, Kleinman HK - Ann N Y Acad Sci (2010) - Review
Studies in various animal models provided scientific foundation for ongoing dermal, corneal, and cardiac wound repair clinical trials.
Limitations: Animal data review.
Kleinman HK, Sosne G - Vitam Horm (2016) - Review
Tb4 accelerates dermal wound repair. Small, abundant peptide with significant wound healing potential.
Limitations: Review of full-length Tb4.
Ho ENM, et al. - J Chromatogr A (2012) - Analytical method
First identification of TB-500 and its metabolites in post-administration equine samples. Confirms TB-500 is the acetylated LKKTETQ fragment of Tb4. Detectable in urine at 0.01 ng/mL.
Limitations: Equine pharmacokinetic study, not efficacy.
Rahman OF, Lee SJ, Seeds WA - J Am Acad Orthop Surg Glob Res Rev (2026) - Review
BPC-157, TB-500, and GHK-Cu promote angiogenesis, integrin-mediated ECM remodeling, and fibroblast activation for wound healing.
Limitations: Review article.
TB-500 is the second most popular healing peptide after BPC-157 on r/Peptides. Almost always discussed in the context of the BPC-157 + TB-500 stack. Community consensus: TB-500 has slower onset but broader systemic healing effects compared to BPC-157's more localized action. Dosing is less frequent (2x/week vs 2x/day) due to higher per-dose amounts. Commonly used for: tendon injuries, muscle tears, joint inflammation, and post-surgical recovery. Main concern: quality control from research chemical vendors. Users report it is well-tolerated with minimal side effects. Note: TB-500 doses are in milligrams (not micrograms like BPC-157), so it is more expensive per cycle.
Research chemical. Not FDA-approved for any indication. Not currently on WADA prohibited list but athletes should verify.
TB-500 is sold as a research chemical. The full-length Thymosin Beta-4 has been in clinical trials (RegeneRx Biopharmaceuticals) but TB-500 as a fragment product is not part of those trials. Not banned by FDA from compounding (unlike BPC-157). Available from research chemical vendors.
Full-length Thymosin Beta-4 has extensive research including Phase 3 clinical trials for ocular repair. TB-500 specifically (the synthetic fragment) has primarily animal data and equine studies. No human clinical trials on TB-500 itself.
Disclaimer: This information is for educational and research purposes only. PepStack does not provide medical advice, diagnosis, or treatment recommendations. Consult a qualified healthcare provider before using any peptide or supplement. Research suggests these compounds may have various effects, but individual results vary and many claims require further clinical validation.